The present invention relates to a manhole cover assembly, and more particularly to a manhole cover having an insert including structure for removal of the manhole cover from a frame.
Manholes are well-known and widely utilized. Generally, a manhole provides access for maintenance of infrastructure, for instance, underground pipelines or cabling. Traditional manhole covers rest on a frame that is attached to the substructure above infrastructure to be maintained. Examples of such substructure include the base for a road or sidewalk. The cover rests on this frame and must be lifted away to gain access to the infrastructure beneath the manhole. Because manhole covers are predominantly made of iron and can weigh in excess of 100 pounds, the effort required to lift a manhole cover can be difficult and even injurious to the operator.
Many attempts have been made to ease the effort required to lift a manhole cover from its frame. Some of these attempts have involved the development of special cover removal tools and corresponding openings in the cover for insertion of the tool into the opening for removal of the cover from the frame. For example, some manhole covers include a hole extending through the cover. To lift the cover, an operator inserts a pointed tool through the hole to either pry up or lift the cover. This method provides some additional lifting leverage, but the hole in the cover provides direct access for external contaminants to drain below to the infrastructure. Other attempts at easing manhole cover removal have been directed at reducing the weight of the cover. One example is the composite manhole cover, which may be formed from a polymer reinforced with fibers such as glass fibers. Unfortunately, many of the cover removal tools developed for use with cast iron covers can be difficult to use with composite covers, because the composite covers cannot be formed with the strength characteristics to support the prying or lifting forces presented by conventional cover removal tools.